BS 15199-2:2006 pdf download – Petroleum products — Determination of boiling range distribution by gas chromatography method — Part 2: Heavy distillates and residual fuels

BS 15199-2:2006 pdf download – Petroleum products — Determination of boiling range distribution by gas chromatography method — Part 2: Heavy distillates and residual fuels 4 Principle A test portion is introduced into a gas chromatographic column, which separates hydrocarbons in the order of increasing boiling point. The column temperature is raised at a linear reproducible rate and the area under the chromatogram is recorded throughout the analysis. Boiling points are assigned to the time-axis from a calibration curve, which is obtained by running a mixture of known normal alkanes covering the test portion boiling range, under the same conditions. From these data, the boiling range distribution is obtained. The recovery at a specified temperature is determined by comparing the area under the chromatogram with that of a reference standard which has been completely eluted. The temperature at which the recovery was measured is recorded. NOTE If the found recovery is less than 100 %, the final boiling point is reported as 720 °C or 750 °C at that recovery. 5 Reagents and materials Unless otherwise stated, only chemicals of recognized analytical quality shall be used. 5.1 Liquid stationary phase, a methyl silicone stationary phase for the column. 5.2 Carrier gases, helium, nitrogen or hydrogen, of at least 99,999 % (V/V) purity. Any oxygen present is removed by a chemical resin filter. Warning Follow the safety instructions from the filter supplier. 5.3 Hydrogen, grade suitable for flame ionisation detectors. 5.4 Compressed air, regulated for flame ionisation detectors. 5.5 Alkanes, normal alkanes of at least 98 % (m/m) purity from C 5 to C 10 , C 12 , C 14 , C 16 , C 18 , C 20 , C 24 and C 28 to be used with Polywax 655 or 1000 (5.6). NOTE The calibration mixture from ISO 3924 [3] is also suitable. 5.6 Polywax 655 or 1000 5.7 Carbon disulfide, with a minimum purity of 99,7 % (V/V). WARNING — Extremely flammable and toxic. NOTE To confirm the suitability of the carbon disulfide as a solvent, it is recommended to check elution profiles (see Figure 2). 5.8 Calibration mixture The mixture shall contain at least one normal alkane with a boiling point lower than the IBP of the sample, and at least one normal alkane with a boiling point close to the temperature at which the recovery is measured. Dissolve 0,1 g of Polywax (5.6) in 7...